There are various forms of skin external preparations such as lotion, milky lotion, and cream. Among them, the lotion is one of the essential items for basic cosmetics. In order to stably blend water-insoluble materials such as perfume, oil components, and oil-soluble agents as well as water and water-soluble material such as a moisturizing component into a lotion, various base-stabilizing technologies (solubilization technologies) with the use of a surfactant have been proposed (for example, refer to patent literatures 1 and 2).
The stability of a base agent can be improved by the suitable selection of a conventional surfactant or by blending a substantial amount thereof. However, it is one of the causes of rough skin, and the improvement of texture in use has not been satisfactory. In recent years, the higher safety of skin external preparations is expected. From this standpoint, the presence of a surfactant was sometimes regarded as a problem. Although the surfactant is an essential component in numerous skin external preparations from the standpoint of the improvement of base agent stability, it is the main cause of rough skin and poor texture in use. Thus, there has been a problem to be solved in that the commercial value of the product is lost on a big scale.
Therefore, from the standpoint that the water-retaining function should be supplied to the skin, the moisturizers such as polyol compounds such as glycerin, sorbitol, and propylene glycol; and mucopolysaccharides such as hyaluronic acid; amino acids as NMF (natural moisturizing factor); agents such as tranexamic acid; and various extracts have usually been blended in skin external preparations as an active component having improving and preventing effects of rough skin. In addition, the method to make up for the stratum corneum barrier function with an occluding agent such as petrolatum ointment and the method to activate skin cells with vitamins, hormones, etc. have been used (for example, refer to patent literatures 3 and 4).
However, in order to enhance a moisturizing effect and a rough skin improving effect, the blending quantity needs to be increased in the case of glycerin or other moisturizers. As a result, the following problems that should be solved are generated. The base agent stability deteriorates and the usability becomes poor. When applied on the skin, it is repelled by sebum and the compatibility with the skin becomes poor. A polysaccharide precipitates in the formulations containing a large amount of alcohol. In the case of amino acids such as DL-threonine, there are drawbacks such as color generation and malodor. The agent such as tranexamic acid has a problem in long-term stability. When an occlusion agent such as petrolatum is used, there is a drawback in that an unpleasant texture such as an oily and sticky feeling is generated. Furthermore, when extracts, vitamins, hormones, and the like are used, there are to-be-solved problems such as safety issues related to side effects and long-term stability.
Thus, the development of a component that has a rough skin improving effect, excellent safety, and excellent texture in use and that can improve base agent stability has been awaited.    Patent literature 1: Japanese Unexamined Patent Publication No. 2001-302443    Patent literature 2: Japanese Unexamined Patent Publication No. 2005-47871    Patent literature 3: Japanese Unexamined Patent Publication No. H9-100225    Patent literature 4: Japanese Unexamined Patent Publication No. H7-277943